Magnetotunable elements for applications in millimeter waveband

Description

Our team provides development and design of easy tunable passive elements for extremely high frequency (EHF) band applications (passband filters, directional couplers, etc). A core of the elements under development is the system of planar photonic crystals formed as periodical microstrip lines and bounded with a special kind of inhomogeneity. The inhomogeneity component can be either a nonmagnetic analog of wire medium (Fig.1b) [1] or a magnetoactive element made of doped manganite, which exhibits left-handed (LH) behavior in EHF band [2]. The operation principle is based on the concept of Tamm states [1,3], which makes the system capable of concentrating the electromagnetic field in the vicinity of the inhomogeneity of a planar photonic crystal.

Fig. 1 shows a laboratory example of a planar filter (a) operating in 9-40 GHz band, based on nonmagnetic wire-medium type of inhomogeneity (b). Fig. 2 shows a laboratory example of magnetotunable EHF-filter based on doped manganite type of inhomogeneity.

The use of doped manganite (LH-switchable medium) provides a broader range of tunability. The production technology includes three successive stages. The bulk samples of LH-switchable medium are synthesized at the first stage. The second stage includes fabrication of thin films from the synthesized bulk targets. The works at the third stage are concentrated on design of magnetotunable elements based on the developed objects. A proper choice of the LH-medium parameters makes it possible to design either broad- or narrowband elements for EHF devices.

a/

b/

Fig.1. EHF filter based on planar photonic crystal with wire-medium type of inhomogeneity

Innovative Aspect and Main Advantages

relatively simple and low-cost production;

operation in a wide frequency range (9 – 40 GHz);

electronic (magnetic) tunability of the parameters of the elements (steepness, position, and intensity of transmission for passband filters; coupling factor for directional couplers, etc);